The Working Principle of Submersible Pumps

There are several types of submersible pumps, categorized by the motor winding design: oil-filled, water-filled, and dry-type.

It is essential to consult the instruction manual before use to avoid errors. If the pump has been idle for an extended period, the impeller must be manually rotated before startup; otherwise, the motor windings may burn out due to the impeller seizing up from prolonged inactivity. Before starting the pump, both the suction pipe and the pump casing must be filled with liquid. Once started, the impeller spins at high speed, causing the liquid within to rotate along with the blades; under centrifugal force, the liquid is flung outward from the impeller. As the ejected liquid enters the diffusion chamber of the pump casing, its velocity gradually decreases while its pressure rises, eventually discharging through the pump outlet and discharge pipe. Meanwhile, the outward displacement of liquid creates a low-pressure vacuum zone-devoid of both air and liquid-at the center of the impeller; driven by atmospheric pressure acting on the surface of the liquid reservoir, liquid flows through the suction pipe into the pump. In this way, liquid is continuously drawn up from the reservoir and discharged through the outlet pipe.